| @altsym(optional)Provides a way of pointing to a user-defined symbol. It must contain an ID of a
                              <symbolDef> element elsewhere in the document.
                           Value conforms to data.URI .
                           att.altsym | 
                  
                     | @arrow(optional)Indicates if an arrowhead is to be drawn as part of the arpeggiation symbol.
                           Value conforms to data.BOOLEAN .
                           att.arpeg.vis | 
                  
                     | @color(optional)Used to indicate visual appearance. Do not confuse this with the musical term
                              'color' as used in pre-CMN notation.
                           Value conforms to data.COLOR .
                           att.color | 
                  
                     | @copyof(optional)Points to an element of which the current element is a copy.
                           Value conforms to data.URI .
                           att.common.anl | 
                  
                     | @corresp(optional)Used to point to other elements that correspond to this one in a generic
                              fashion.
                           One or more values from data.URI , separated by spaces.
                           att.common.anl | 
                  
                     | @evaluate(optional)Specifies the intended meaning when a participant in a relationship is itself a
                              pointer.
                           Allowed values are:
                           "all " (If an element pointed to is itself a pointer, then the target of that pointer
                              will be taken, and so on, until an element is found which is not a pointer.) ,  "one " (If an element pointed to is itself a pointer, then its target (whether a pointer
                              or not) is taken as the target of this pointer.) ,  "none " (No further evaluation of targets is carried out beyond that needed to find the
                              element(s) specified in plist or target attribute.)att.targeteval | 
                  
                     | @facs(optional)Permits the current element to reference a facsimile surface or image zone which
                              corresponds to it.
                           One or more values from data.URI , separated by spaces.
                           att.facsimile | 
                  
                     |  | 
                  
                     |  | 
                  
                     | @fontsize(optional)Indicates the size of a font expressed in printers' points, i.e., 1/72nd of an inch,
                              relative terms, e.g., "small", "larger", etc., or percentage values relative to "normal"
                              size, e.g., "125%". 
                           Value conforms to data.FONTSIZE .
                           att.typography | 
                  
                     |  | 
                  
                     |  | 
                  
                     | @glyphname(optional)Glyph name.
                           Value of datatype string .
                           att.extsym | 
                  
                     | @glyphnum(optional)Numeric glyph reference in hexadecimal notation, e.g. "#xE000" or "U+E000". N.B.
                              SMuFL version 1.18 uses the range U+E000 - U+ECBF.
                           Value of datatype a string matching the following regular expression: "(#x|U\+)[A-F0-9]+" .
                           att.extsym | 
                  
                     | @ho(optional)Records a horizontal adjustment to a feature's programmatically-determined location
                              in terms of staff interline distance; that is, in units of 1/2 the distance between
                              adjacent staff lines.
                           Value conforms to data.MEASUREMENTREL .
                           att.visualoffset.ho | 
                  
                     | @label(optional)Provides a name or label for an element. The value may be any string.
                           Value of datatype string .
                           att.commonPart | 
                  
                     | @layer(optional)Identifies the layer to which a feature applies.
                           One or more values of datatype positiveInteger , separated by spaces.
                           att.layerident | 
                  
                     | @n(optional)Provides a number-like designation for an element.
                           Value conforms to token .
                           att.common | 
                  
                     | @next(optional)Used to point to the next event(s) in a user-defined collection.
                           One or more values from data.URI , separated by spaces.
                           att.common.anl | 
                  
                     | @order(optional)Describes the direction in which an arpeggio is to be performed.
                           Allowed values are:
                           "up " (Lowest to highest pitch.) ,  "down " (Highest to lowest pitch.) ,  "nonarp " (Non-arpeggiated style (usually rendered with a preceding bracket instead of a
                              wavy line).)att.arpeg.log | 
                  
                     | @plist(optional)Contains a space separated list of references that identify active participants in
                              a
                              collection/relationship, such as notes under a phrase mark; that is, the entities
                              pointed "from".
                           One or more values from data.URI , separated by spaces.
                           att.plist | 
                  
                     | @prev(optional)Points to the previous event(s) in a user-defined collection.
                           One or more values from data.URI , separated by spaces.
                           att.common.anl | 
                  
                     | @sameas(optional)Points to an element that is the same as the current element but is not a literal
                              copy of the current element.
                           One or more values from data.URI , separated by spaces.
                           att.common.anl | 
                  
                     | @staff(optional)Signifies the staff on which a notated event occurs or to which a control event
                              applies. Mandatory when applicable.
                           One or more values of datatype positiveInteger , separated by spaces.
                           att.staffident | 
                  
                     | @startid(optional)Holds a reference to the first element in a sequence of events to which the feature
                              applies.
                           Value conforms to data.URI .
                           att.startid | 
                  
                     | @subtype(optional)Provide any sub-classification for the element, additional to that given by its type
                              attribute.
                           Value of datatype NMTOKEN .
                           att.typed | 
                  
                     | @synch(optional)Points to elements that are synchronous with the current element.
                           One or more values from data.URI , separated by spaces.
                           att.common.anl | 
                  
                     | @to(optional)Records a timestamp adjustment of a feature's programmatically-determined location
                              in terms of musical time; that is, beats.
                           Value conforms to data.TSTAMPOFFSET .
                           att.visualoffset.to | 
                  
                     | @tstamp(optional)Encodes the onset time in terms of musical time, i.e.,
                              beats[.fractional_beat_part].
                           Value conforms to data.BEAT .
                           att.timestamp.musical | 
                  
                     | @tstamp.ges(optional)Captures performed onset time in several forms; that is, ppq (MIDI clicks and
                              MusicXML 'divisions'), Humdrum **recip values, beats, seconds, or mensural duration
                              values.
                           Value conforms to data.DURATION.gestural .
                           att.timestamp.performed | 
                  
                     |  | 
                  
                     | @type(optional)Characterizes the element in some sense, using any convenient classification scheme
                              or typology.
                           Value of datatype NMTOKEN .
                           att.typed | 
                  
                     | @vo(optional)Records the vertical adjustment of a feature's programmatically-determined location
                              in terms of staff interline distance; that is, in units of 1/2 the distance between
                              adjacent staff lines.
                           Value conforms to data.MEASUREMENTREL .
                           att.visualoffset.vo | 
                  
                     | @when(optional)Indicates the point of occurrence of this feature along a time line. Its value must
                              be the ID of a when element elsewhere in the document.
                           Value conforms to data.URI .
                           att.alignment | 
                  
                     | @x(optional)Encodes an x coordinate for a feature in an output coordinate system. When it is
                              necessary to record the placement of a feature in a facsimile image, use the facs
                              attribute.
                           Value of datatype decimal .
                           att.xy | 
                  
                     | @xml:base(optional)Provides a base URI reference with which applications can resolve relative URI
                              references into absolute URI references.
                           Value conforms to data.URI .
                           att.commonPart | 
                  
                     | @xml:id(optional)Regularizes the naming of an element and thus facilitates building links between it
                              and other resources. Each id attribute within a document must have a unique
                              value.
                           Value of datatype ID .
                           att.id | 
                  
                     | @y(optional)Encodes an y coordinate for a feature in an output coordinate system. When it is
                              necessary to record the placement of a feature in a facsimile image, use the facs
                              attribute.
                           Value of datatype decimal .
                           att.xy |